| Author |
Message |
    
Kd4amg
Intermediate Member
Username: Kd4amg
Post Number: 192
Registered: 6-2003
| | Posted on Wednesday, December 07, 2005 - 12:03 am: | 
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I got a used hr - 2510 already modified for cb use...I took the TOP cover off ( the one you adjust all the inside important pots for ) and now when I try to put the TOP cover back on, the rig shows a different RF OUTPUT ( dont know if it is a squeal or not ). I have it dead-keying 4 watts AM , but when I try to put the TOP cover back on the rf meter can jump up to 6 - 10 watts.
I tried tightening all the screws around the outer edge ( other half of the case ) of the radio, but other wise I have no idea what is causing this....? This has to be something real simple I am overlooking. I am using the rig in the house on a 14 amp regulated ac/dc power supply and using the stock hand mike. This even does it with the mike UNPLUGGED ( using the "tx switch " on front of the 2510 ) and it still does it.
The dood I bought the rig from said " mike squealed every now and then on transmit " so this apparently had been a problem for some time ( sometimes squeal and sometimes not ) with this rig,,,can any one offer any suggestions besides leaving the TOP COVER off since it might be used in the house anyway ? I did try running a jumper wire across the rig from left side to right side and it would NOT squeal.
This totally has me bumfuzzled.
Thanks in advance
Robert ...it HAS to be something extremely simple I am overlooking. |
Therealporkchop
Advanced Member
Username: Therealporkchop
Post Number: 503
Registered: 11-2002
| | Posted on Wednesday, December 07, 2005 - 1:08 pm: |
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I had a Mirage 44 that did this on transmit but it was when you put the top cover on, the one on the solder side of the board.
Nothing I ever did would stop it. The problem turned out to be the super mod that was installed in this radio. In these radios it is usually done at R-238. It was more of a self-oscillation problem than an actual mic squeal, but none-the-less it squealed.
With the top cover off, no problems. Regardless of a wire or not, it did it. If your radio doesn't do it with a wire with the cover on, then I'd think maybe you had a short somewhere. There are a bunch of things you could have wrong, but it's hard to say without seeing it.
I finally removed the super mod, and sold the radio without a squeal. So who knows what the actual problem was.
Good luck. |
Kd4amg
Intermediate Member
Username: Kd4amg
Post Number: 194
Registered: 6-2003
| | Posted on Wednesday, December 07, 2005 - 2:58 pm: |
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Now I have discovered something else... when the TOP COVER is ON ( all 4 screws in place ) there is a carrier on SSB after ( but not before ) only after you speak or whistle into the microphone...the rf power goes up to about 20 - 25 watts on either ssb ( usb or lsb ), and the carrier transmits around 15 watts continiously until you let go of the PTT switch on the mike, then it will do it again when you try transmitting on ssb. ....methinks some one before me has turned a vr control or a pot too far trying to get an extra watt or two out of it and that it needs a complete transmitter realignment from beginning to end...or a cold solder joint ...or a bad connection is made / broken when you put the TOP COVER back on...it works great on am & ssb with the TOP COVER completely off.
Ideas ? ( well, besides the " leave top cover off permanently " idea...!!! ) hee hee hee 
Robert |
Tech291
Moderator
Username: Tech291
Post Number: 317
Registered: 11-2004
| | Posted on Wednesday, December 07, 2005 - 3:25 pm: |
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Robert,
time to get out the magnifier and check the board and traces around IC-105 for cracks or bad soldering.VR-106 is the carrier balance trimmer.
tech291
cef#291
kc8zpj
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Semi
Junior Member
Username: Semi
Post Number: 12
Registered: 7-2005
| | Posted on Thursday, December 08, 2005 - 8:25 am: |
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Sometimes older 2510's develop a ground loop because the 477 final is bolted directly to the case. Try putting an insulator behind the 477 as is normal with other radios.
Have heard of this happening but haven't experienced it myself.
Worth a try, simple and cheap.
Also the swr usually rises with the cover off.
Good luck
Semi |
Thehobo
Junior Member
Username: Thehobo
Post Number: 37
Registered: 2-2004
| | Posted on Thursday, December 08, 2005 - 1:17 pm: |
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also if the radio is super? peaked, with top off, it, like said above, can create ossilation of rf!!
when the top is put back on?? if carrier present on sideband, someone mite of tried to (super), peak the bias, there creating a carrier?? ive ran into this at times..
thehobo
274150 am
monitor ch. |
Kd4amg
Intermediate Member
Username: Kd4amg
Post Number: 197
Registered: 6-2003
| | Posted on Friday, December 09, 2005 - 7:41 pm: |
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...ok here is what happened ( in THIS situation)... took it to local cb shop. He replaced a crystal that made me transmit 3 kc low on AM....brought rig home...same problem as before....so I called the cb tech on phone . He said "bias must be off a bit". So I took cover off and looked for a internal control named "bias ", but found " vr 112 & vr 113" ( vr 113 was at the right rear corner of rig, near where one cover screws attach on outside. So I found my itty-bitty screwdriver and turned vr-113 from the 12 noon poistion to left to the 10 o clock position. Put cover back on and NO PROBLEMS !!
Then I talked on radio all yesterday evening, good reports from every one.
I took rig back to shop that repaired the crystal and told him what I did...he took cover off, hooked up a multimeter to rig and said " you did good, that you turned it back (vr 113 ) to where it should be and it fixed your problem".
So now rig is fixed and I am happy.
GUESS --- who ever had rig before me sometime in its past had turned that vr-113 to try to paek it out, and left it, not knowing . If you happen to have a hr-2510 and want to look for yourself to see what occurred, just take the TOP cover off ( not the one with the speaker on it ) and look thru this post to see what was done.
If you happen to have this or a similar problem in the future, you might try MY solution or one that is mentioned in another person s post above this one.
Thanks to all.
Robert |
Black_hawk
New member
Username: Black_hawk
Post Number: 9
Registered: 2-2005
| | Posted on Thursday, December 15, 2005 - 10:37 pm: |
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Hello,Do you know what vr 113 is for?
Thanks. |
Tech291
Moderator
Username: Tech291
Post Number: 325
Registered: 11-2004
| | Posted on Thursday, December 15, 2005 - 11:14 pm: |
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Black hawk,
in the uniden hr-2510 vr-113 is driver bias and vr-112 is final bias.
tech291
CEF#291
KC8ZPJ |
Tech808
Moderator
Username: Tech808
Post Number: 8656
Registered: 8-2002
| | Posted on Friday, December 16, 2005 - 7:26 am: |
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Black_hawk,
LOOK to the LEFT of the Forum here and you will see:
Tools
Mic. Wiring
Frequency Chart
CB & Ham Lingo
Modification List
CLICK on Modification List
When you get there under (Make) scroll down until Uniden comes up, then on Model scroll down until you see HR-2510.
HR-2510 is the Last radio listed under Model.
It will give you the VR Adjustments and tell you what they are for.
Hope this helps,
Lon
TEch808
CEF808
N9OSN
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